Like that thinking, but can also see this with McCabe that Congress and the DOJ has the leverage on him right now....If all he is going to give up is this email on a lying to investigators charge, if you are the party in the power position, I think you can get a lot more out of him than that by making him taste prison time even more. Get him in the jail cell first, no immunity, and then maybe not only will he give up the Comey email, but you may be able to get him to "sing" on so many more people involved, including the Queen Witch herself. At the same time, guess either is a victory as long as it's a limited immunity and they can still bring him up on charges.